text: An example is the conversion of the aquo complex [Co(NH)(HO)] with bromide to give pentamminecobalt(III) bromide complex:
  :[Co(NH)(HO)]  +  Br   →   [Co(NH)Br]  +  HO
  The mechanism of such reactions often invoke ion-pairing of the entering anion in the second coordination sphere followed by dissociation of the aquo ligand.